Method of making castings



July 7, 1925.

N. M. AUSTIN METHOD OF MAKING CASTNGS Filed March 5, 1923 INVENTOR Petented July 7, 1925,."

y .1544544 UNITE'D -..j.ST ATES" PATENT OFF CE.

NED u. nUs'rIm or CANTOE 0319,. nsSIGNo To UNITED ENGINEEBING AND FOUNDBY comum, OF PITTSBUB E, PENNSYLVAHIA, A CORPOBA'rION OF 'HE'D or MAKING CATmGs.

A i flo med much '6, 1923. Seria No. 322,841.

To all 'wlwm t may oMem: l

vBe it known that I, M.` A TIN, a citizen of the Unitetetes, residing at Canton, in the 'c nty of Stark'andState of Ohio, have invented a new and useful Improvement in 'Methods of Making-Cstings', of which 'the' following 'is a. fu11, q1ear, and exactdescription, A v The present invention relate -broadly" to the art of' nolding, and more ?particularly to an improved method of maing cstings. In 'making "certain types-of `.ca t-1ns,- par ticu'larly :eest rol1s, ityhas heretofore been the practice, in order .to obtain the desired (lepth of chill, "to employ &composition of meta] having thef -rope rty' offre ezing quickly. `The.quick. "eezin'g, however, does .not allow Suflieieft 'time for the phite to Separate out enough to "givefa soid gray interior to the Casting. The quicl. freezing also has a tendeney 'to 'set upcasting strains;

which; when &Casting is broken,"how in the 'form of radial streaks -from the Su rface towards-the center. f

'By 'the present invention I fovercome the above mentioned, an

` advantages of the prior practice;byeflecting e change in the chemical and: hysicel interior structure of e eastingji aj erzthe' moiten metal ha-S been poured into the mold, and preferably after the" si'lperficl l ortion of the 'm oiten metal has oooled and So idified 'to 'form an outer Shell. This change is .pr0-' duced by causing the diffusion into the in terior of the molten 'motel-'of a .different motel or materil. The' invention is of particularzimportance in connection with the' Casting of rolls, it bein desirable, for -example,` to lower the me ting point of the mctal of which the interior of 'the castingie com osed in order that' 'this ortion of the castlng will not oool too quic y.

Two slightly' diflerent methods; for rv ,tieing my. invention' are illustrated in ]the eeo npanying drawings, in which`- 1 tiene views of a mold illustrating one -method of carrying my invention into ef- Flgure 3 is a view similar to Figu method; and v i, Figure is a Section ai view of a. toll cust- Eng made in accordance th my inventiou o os to other dis v interior -ofthe ro res 1 and 2 are similar ertical secres 1 and 2, iliustrating a slightly modified Referring to. the draWingiA represent' zont al pasages 3 'ani- ,4, constituting the gate,""f0r` introducin the molten material 'into the mold, and thefris er venta 5, While I hve shown a" mold -for Casting rol1s,- it' willbeunderstood that my inyention is not li'mited to rolls, but isnppliceble tocastin genera11 irresPect-iveo ,Shape or intended A l l in Eigur es 11and 2, "a pipe 6 -is `"intro duoe( l into the moldihrough a riservent 5 prior to the pouring of the 'molten metl into the mold. 'The lower end of the pipe to the heat of' the molten met l ,Surrounlin the-pipe. The molten motel. i now poure into the mold and the superfieialportion of the i'etal surro unding. the ;..pipe may be almaterial,- 'whioh mi'ybe 'aothei'meth for instano'e and 'the pipe gradually withdrawn from the mold to allow the moltenmaterial containedwithin itio difl'use into the molten 'metal inth'e' 'interim` `of the Shell, .thereby tothe froz en helL V A In Fiure 3,`.`I- --have` illustrated'eelight modification of theabove .described method. According' tothis method, a bar ?of differept chemical anlysi `ie inserted 'down through a' molten mass of metal in a mold,

changing: the' coinpoition of the estin'g up "said ber melting 'and difl'usingfinto the surrounding motel a-in 'the first-method.

. It will be understood, of eourse, that'. in the case offroll the object ia to obtain extreme In accordance -with the method illustrated is'closedby a well of the mold an'd. the pipe is of s'ome material which will' not melt when subjected 1 hardnese in the outer portion of the roll :for

a considerable de th 'While giving' to' the great tensile strength. By theintroduction of various metais, in the mnner' 'above described, and containing varying roportions of silicon; manganese,

carbon, c romium,molybdenum, niekol, coppe'r, cobalt,` tungsten, titnium, aluminum and the like, I am .enabled to change the internal 'structure of .a 'Tell c sting so as to reatly 'increase the strength of the'roll, and

'am at the same time enabledto'ehill to structure of the Casting,

the desired depth. In fact, the present invention enables chilling to greater depths than formerly Without weakening the roll.

In Figure 4 I have illustrated a roll casting made in accordance with either of the methods above described.

I claim;

1. The method of making a Casting, which comprises causing the difijusion. into the interior of a mass of molten metal in a mold of material adapted to change the internal substantially. as described. v

2. The method of making a Casting, Which comprises filling a mold with molten metal, allowing the superficial portion of the metal to COOl and solidify to form a Shell, and then causing the difl'usion into the interior of the molten metal of material adapted to change the internal structure of the Casting, substantially as described.

3. The method' of making a Casting, which comprises providing a mass of molten metal in a mold with a core composed of material adapted to difi'use into Said molten metal and change the internal structure of the easting, substantially as described.

4. The method of making a Casting, which comprises causing the diffusion into the interior of amass of molten metal in a mold, of material adapted to lower the melting point of the interior' portion of the Casting, substantially' as described.

5. The method of making a Casting, which comprises filling a mold with molten metal, and then introducing into the interior of the molten metal material in a molten state adapted to diffuse into said molten metal and change the internal structure of the casting, substantially as described.

6. he method of making a Casting, which comprises filling a mold with molten metal, allowing the Superficial portion of the metal to cool and Soldify to form a Shell, and

then introducing into the interior of the moltenmeta l material in a molten state adapted to difi'use into .Said molten metal and change the internal structure of the castinlg, substantially as described.

7. he method of makin a castin ,which comprises filling a mold with quick eezing molten material, and causing the diffusion into the interior *of the molten mass of material adapted to give the Casting a solid gray interior, substantially as described.

8. The method of making a Casting, which comprises inserting a tube into a mold so that its lower end iS closed by a wall of the mold, filling said mold with molten metal, then filling Said' tube with molten material having different characteristics from said molten metal, and then Withdrawing said tube from the mold, substantially as described. y 9. The method of making a one piece Casting having inner and outer portions of different analyses, comprising pourin molten metal about a core in a mold an during the hardening of the metal from the exterior toward the cored portion of the Casting causing the diffusion into the mass of molten metal Which surrounded the core of material to change the analysis of the interior of' the Casting, substantially as described.

10. The method of making a one piece Casting having inner and outer portions of different analyses, comprising pouring molten metal about a hollow core and after the surface of the metal contacting with the mold has hardened, pouring molten metal of a different analysis into the interior of the' core, and then Withdrawing the core to permit the admixture of the two molten metals, substantially as described. 11. The method of Casting a one piece roll having a chilled surface, comprising making up a mold for the roll to be cast With a hollow core extending through the aXis of the roll cavity in the mold, pourin metal into the cavit about the core an' pouring metal of diflrent'composition into the interior of the core, and thenwithdr w` ing the core to permit the molten metal in the core to mix with that on the exterior of the core after the outer surface of the roll has been chilled and Solidified to the desired de th, substantially as described.

n testimony whereof I have hereunto set my hand.

NED M. AUSTIN. 

